Excerpts from:
What is Salivary Gland Cancer?
Cancer Reference Information
American Cancer Society website
http://www.cancer.org/eprise/main/docroot/CRI/content/CRI_2_4_1X_What_is_salivary
_gland_cancer_54
As of 2001
Types of salivary gland tumors
Normal salivary glands are made up of several different types of cells;
tumors can start from any of the cell types. Salivary gland tumors are
named according to which of these cell types they most resemble when viewed
under a microscope. The cancers are also given a numeric grade of 1, 2,
or 3 based on their appearance under a microscope.
Grade 1 (also called low-grade or well-differentiated) cancers look very
much like normal salivary gland cells and tend to grow slowly and have
a good outcome.
Grade 3 cancers (also called high-grade or poorly differentiated) look
quite different from normal cells, often grow and/or spread quickly, and
have a poor prognosis or outlook.
Grade 2 cancers (also called intermediate-grade or moderately differentiated)
have an appearance and outlook that is between grade 1 and grade 3 cancers.
Benign tumors do not spread from the salivary gland to other parts of
the body and are almost never life-threatening. Removing them surgically
almost always cures them. Very rarely, benign tumors may become malignant
if left untreated for a long period of time or if they are not completely
removed and recur (grow back) several times. Only malignant (cancerous)
tumors of the salivary glands will be discussed in this document.
Under “…Statistics” Heading:
…The survival rates for malignant salivary gland tumors depend on
the cell type and the stage of the cancer. The stage of the cancer depends
on its size and whether or not it has spread to other parts of the body.
Staging is discussed in detail in the section "How is Salivary Gland
Cancer Diagnosed?"
How Is Salivary Gland Cancer Staged?
Staging is the process of finding out how far a cancer has spread. The
prognosis (the outlook for survival) for people with cancer depends, to
a large extent, on the cancer's stage. The stage of a salivary gland cancer
is the most important factor in selecting treatment options. Staging information
is obtained from the physical exam, imaging studies (CT scan, MRI, chest
x-ray) and biopsy results.
The American Joint Committee on Cancer (AJCC) TNM System
The most common system used to describe the stages of salivary gland cancer
is the TNM system.
T refers to the size of the primary Tumor and if the cancer has spread to tissues near the salivary glands.
N describes the extent of spread to regional (nearby) lymph Nodes through special lymphatic channels. Lymph nodes are small bean-sized collections of immune system cells that are important in fighting infections and disease. Cells from salivary gland cancer can enter these lymphatic channels and reach lymph nodes in the neck area.
M indicates whether the cancer has Metastasized (spread) to other organs of the body.
Using the TNM staging system, information about the tumor, lymph
nodes, and metastasis is combined to assign a stage. This process is called
stage grouping. The stage is described in Roman numerals from I to IV.
Your chance for cure is better if the stage of your cancer is low. If
you have any questions about your stage or how it affects your treatment
options, ask your doctor.
Stage I:
- The cancer is smaller than 4 centimeters (11/2 inches). It has not spread
outside the salivary gland.
Stage II:
- The cancer has spread outside the gland to surrounding face or neck
tissues or,
- The cancer is between 4 centimeters (11/2 inches) and 6 centimeters
(21/2 inches) and has not spread outside the gland.
Stage III:
- The cancer is smaller than 11/2 inches but has spread to one nearby
lymph node on the same side of the neck that is smaller than 3 centimeters
(11/4 inches).
Stage IV
- The cancer is larger than 6 centimeters (21/2 inches) or
- The cancer invades into the facial nerve (runs through the parotid gland)
or the base of the skull or
- The cancer is between 4 centimeters (11/2 inches) and 6 centimeters
(21/2 inches) and has spread to one nearby lymph node on the same side
of the neck that is smaller than 3 centimeters (11/4 inches) or
- The cancer is any size and has spread to one nearby lymph node on the
same side of the neck that is larger than 3 centimeters (11/4 inches)
or has spread to several nodes of any size on either side of the neck
or
- The cancer has spread to distant organs
When all types of salivary gland cancer are considered together, the 10-year
survival rate for stage I is about 90%. For stage II cancers, it is 65%
and it is 22% for stage III cancers. It is lower for stage IV. These
are only approximate numbers because your survival will also depend on
the grade and type of your cancer.
The 10-year survival rate refers to the percentage of patients who live
at least 10 years after their cancer is diagnosed. Many of these patients
live much longer than 10 years after diagnosis, and 10-year rates are
used to produce a standard way of discussing prognosis. Ten-year relative
survival rates exclude from the calculations patients dying of other diseases,
and are considered to be a more accurate way to describe the prognosis
for patients with a particular type and stage of cancer. Of course, 10-year
survival rates are based on patients diagnosed and initially treated more
than 10 years ago. Improvements in treatment often result in a more favorable
outlook for recently diagnosed patients.
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